Helicopter

ABSTRACT

A helicopter having: a flow control device provided at one of a lower portion of a side surface of a fuselage and a portion on a lower surface of the fuselage near the side surface and extending downward.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The invention relates to a helicopter, and more particularly to ahelicopter having a downwash flow control function.

[0003] 2. Description of Related Art

[0004] Spraying of chemicals or fertilizers using a helicopter has beenput into practice in an agricultural field or the like. In such sprayingoperation, the helicopter generally maintains low speed almost hoveringat the height of having high influence of ground effect so as to adherethe chemicals in mist even to the backside of leaves of crops to besprayed, effectively utilizing the downwash generated by the rotation ofa rotor of the helicopter.

[0005]FIG. 6 shows a downwash flow generated by the rotor rotation ofthe helicopter. It has been known that, as shown in FIG. 6, the downwashD flows downward at high speed along fuselage side surfaces 110 of ahelicopter 100 and separates at a fuselage lower surface 120 to produceirregular air current C. Therefore, when spraying nozzles are disposedat the lower surface 120, the irregular air current C causes lots ofchemicals to adhere to the lower surface 120, and the adhered chemicalsfall as droplets or a part of chemicals is sometimes not sprayed,resulting in lower spraying efficiency. In order to avoid this, nozzles200 are often disposed apart from a fuselage 101 of the helicopter 100as shown in FIG. 7.

[0006] Recently, various kinds of technologies have been proposed forcontrolling such downwash flow. For instance, such a technology isdisclosed that, by providing a flow control device (a forming member, adrift plate, a cover, etc.) at the upper part of a helicopter fuselage,a rescuer or a worker positioned under the fuselage can avoid beingdirectly exposed to a strong downwash (see, for example,JP-Tokukaihei-7-47998A).

[0007] When spraying chemicals using a helicopter, it is effective todiffuse the chemicals by the downwash generated by the rotor rotation ofthe helicopter. However, the technology described in aboveJP-Tokukaihei-7-47998A would lead to a problem that it cannoteffectively utilize the downwash.

[0008] If adopted the technology that uses nozzles disposed apart fromthe helicopter fuselage (see FIG. 7), supporting members having nozzlesmounted thereon need to be long in order to avoid adhesion of chemicalsto the lower part of the fuselage due to the downwash, resulting inweight increase of the helicopter. Accordingly, it has long been desiredto develop a new technology for reducing the weight of a helicopter andsimultaneously for improving spraying efficiency.

[0009] When spraying chemicals or the like, the helicopter keeps lowspeed almost hovering flight at the height of having high influence ofground effect as described before, and therefore the generation ofirregular air current under the fuselage due to the downwash leads to aproblem of impairing the stability of the body during flight, andreducing controllability.

SUMMARY OF THE INVENTION

[0010] An object of the invention is to provide a helicopter for use inspraying chemicals or the like, which improves spraying efficiency bypreventing the chemicals from adhering to the lower surface of afuselage with effective use of a downwash, and improves stability andcontrollability of the body during flight such as spraying flight inwhich low speed almost hovering is sustained at the height of havinghigh influence of ground effect.

[0011] In accordance with a first aspect of the present invention, ahelicopter comprises: a flow control device provided at one of a lowerportion of a side surface of a fuselage and a portion on a lower surfaceof the fuselage near the side surface and extending downward.

[0012] According to the helicopter of the first aspect of the invention,with the flow control device provided, extending downward, at one of thelower portion of the fuselage side surface and the portion on the lowersurface of the fuselage near the side surface, the downwash flowingalong the fuselage side surfaces is guided outward apart from thefuselage, maintaining a steady flow. Therefore, the downwash reaches theground surface as a steady flow irrespective of the fuselage, allowingchemicals or the like to be effectively diffused when the helicoptersprays the chemicals or the like.

[0013] Also, according to the helicopter of the first aspect of theinvention, the flow control device also prevents the downwash fromflowing into the under side of the fuselage, which suppresses generationof irregular air current under the fuselage. This air current preventsthe chemicals from adhering to the fuselage lower surface when thehelicopter sprays the chemicals or the like, to thereby improve sprayingefficiency and also eliminate removing work of the chemicals adhering tothe fuselage lower surface.

[0014] Further, according to the helicopter of the first aspect of theinvention, since the flow control device suppresses the generation ofirregular air current under the fuselage, the body posture can bestabilized, and further body controllability can be remarkably improvedduring the flight such as the spraying flight in which low speed almosthovering is sustained at the height of having high influence of groundeffect.

[0015] In accordance with a second aspect of the present invention, ahelicopter comprises: a flow control device provided at one of a lowerportion of a side surface of a fuselage and a portion on a lower surfaceof the fuselage near the side surface, for guiding a downwash flowingalong the side surface of the fuselage to flow apart from the fuselage.

[0016] According to the helicopter of the second aspect of theinvention, with the flow control device provided, extending downward, atone of the lower portion of the fuselage side surface and the portion onthe lower surface near the side surface of the fuselage, the downwashflowing along the fuselage side surfaces is guided outward apart fromthe fuselage. Accordingly, the downwash can generate a circulating flowat the sides of the fuselage, allowing chemicals or the like to beeffectively diffused when the helicopter sprays the chemicals or thelike.

[0017] Also, according to the helicopter of the second aspect of theinvention, the flow control device is provided at one of the lowerportion of the fuselage side surface and the portion on the lowersurface of the fuselage near the side surface so that the downwashflowing along the fuselage side surfaces is guided outward apart fromthe fuselage, which prevents the downwash from flowing into the underside of the fuselage. This suppresses generation of irregular aircurrent under the fuselage. Accordingly, when the helicopter sprays thechemicals or the like, the chemicals are prevented from adhering to thefuselage lower surface, resulting in improvement of spraying efficiencyand also elimination of removing work of the chemicals adhering to thefuselage lower surface.

[0018] Further, according to the helicopter of the second aspect of theinvention, Since the flow control device suppresses the generation ofirregular air current under the fuselage, the body posture can bestabilized, and further body controllability can be remarkably improvedduring the flight such as the spraying flight in which low speed almosthovering is sustained at the height of having high influence of groundeffect.

[0019] In accordance with a third aspect of the invention, a helicoptercomprises: a projection member provided at one of a lower portion of aside surface of a fuselage and a portion on a lower surface of thefuselage near the side surface and projecting downward.

[0020] According to the helicopter of the third aspect of the invention,since the projecting member is provided projecting downward at one ofthe lower portion of the fuselage side surface and the portion on thelower surface of the fuselage near the side surface, the downwashflowing along the fuselage side surfaces is prevented from flowing intothe under side of the fuselage. This suppresses generation of irregularair current under the fuselage. Accordingly, when the helicopter spraysthe chemicals or the like, the chemicals are prevented from adhering tothe fuselage lower surface, resulting in improvement of sprayingefficiency and also elimination of removing work of the chemicalsadhering to the fuselage lower surface.

[0021] Also, according to the helicopter of the third aspect of theinvention, since the projecting member suppresses the generation ofirregular air current under the fuselage, the body posture can bestabilized, and further body controllability can be remarkably improvedduring the flight such as the spraying flight in which low speed almosthovering is sustained at the height of having high influence of groundeffect.

[0022] Preferably, the helicopter further comprises a flow channelwithin the fuselage for guiding a downwash on an upper side of thefuselage to a lower side of the fuselage.

[0023] Accordingly, since the flow channels are provided within thefuselage for guiding the downwash on the upper side of the fuselage tothe lower side of the fuselage, the air is replenished to the lowerspace of the fuselage, which always keeps the pressure of the lowerspace positive. This positive pressure securely prevents the downwashflowing along the fuselage side surfaces from flowing into the lowerside of the fuselage, thereby effectively suppressing the generation ofirregular air current at the lower side of the fuselage.

BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The present invention will become more fully understood from thedetailed description given hereinafter and the accompanying drawingswhich are given by way of illustration only, and thus are not intendedas a definition of the limits of the present invention, and wherein;

[0025]FIG. 1 is a front view of a helicopter according to a firstembodiment of the present invention;

[0026]FIG. 2 is a side view of the helicopter shown in FIG. 1 (with aflow control plate provided at an almost entire length of a lowerportion of a fuselage side surface);

[0027]FIG. 3 is a side view of the helicopter shown in FIG. 1 (withdivided flow control plates provided separately at the lower portion ofthe fuselage side surface);

[0028]FIG. 4 is a front view of a helicopter according to a secondembodiment of the present invention;

[0029]FIG. 5 is a sectional side view of the helicopter shown in FIG. 4.

[0030]FIG. 6 is a front view of a helicopter of an earlier technique;and

[0031]FIG. 7 is a front view of the helicopter of FIG. 6 provided withnozzles for spraying chemicals.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0032] Embodiments of the invention will be described in detail withreference to the drawings.

First Embodiment

[0033] Referring to FIGS. 1 to 3, a construction of a helicopter 1according to the first embodiment will be explained. The helicopter 1comprises a fuselage 2, a main rotor 4 attached to the upper portion ofthe fuselage 2 via a rotor shaft 3, skids 5 attached to the lowerportion of the fuselage 2, a tail boom 6 coupled to the fuselage 2 atits rear side, a tail rotor 7 attached to a rear tip of the tail boom 6,flow control plates 8 mounted on the lower portions of both sidesurfaces 2 a of the fuselage 2, and the like (see FIGS. 1 and 2). Thehelicopter 1 is used for spraying chemicals or fertilizers, and providedwith spraying nozzles (not shown) on a lower surface 2 b of the fuselage2.

[0034] Installed at the inside of the fuselage 2 are a pilot's seat, acargo compartment, and further an engine for driving the main rotor 4and the tail rotor 7, and control devices such as a cyclic stick, acollective stick and a pedal. Rotation of the main rotor 4 driven by theengine generates a downwash D as shown in FIG. 1.

[0035] The flow control plates 8 are one example of a flow controldevice and a projecting member of the invention, and attached to thelower portions of both side surfaces 2 a of the fuselage 2, projectingdownward on a slant (right-side downward and left-side downward in FIG.1). That is, the flow control plates 8 look truncated chevron shapedwhen viewed from the front of the helicopter 1 (see FIG. 1). The flowcontrol plates 8 guide the downwash D, which flows along both sidesurfaces 2 a, right-side downward and left-side downward of FIG. 1,respectively, so as to flow apart from the fuselage 2, preventing thedownwash D from flowing into a lower space U of the fuselage 2.

[0036] The flow control plates 8 are provided at the lower portions ofboth side surfaces 2 a of the fuselage 2, extending to a front-and-reardirection. The plates 8 may be provided, extending to the front-and-reardirection, at almost entire length of the lower portions of both sidesurfaces 2 a (see FIG. 2), or dividedly provided at front portions B,center portions C and rear portions D (see FIG. 3). The plates 8 can bemade of various metals, various synthetic resins, various rubbermaterial, wood, and composite material composed of these materials.

[0037] The height of each flow control plate 8 (length in a directionnormal to the fuselage side surface 2 a) is set to larger value than thethickness of a boundary layer on the side surface 2 a. While thedownwash D flows along both side surfaces 2 a, it has higher flowingspeed in the area apart from the side surface 2 a by a certain distance(the thickness of the boundary layer) under less influence of viscosity.On the other hand, the downwash D flows at low speed in the area closeto the side surface 2 a (in the boundary layer) under the influence ofviscosity. Therefore, in order to control the downwash D by the flowcontrol plates 8, the height of the plate 8 needs to be set to largervalue than the thickness of the boundary layer. In the embodiment, theheight of the plate 8 is set to about 40 mm.

[0038] In the helicopter 1 of the embodiment, the downwash D flowingalong both side surfaces 2 a is guided, by the flow control plates 8mounted at lower portions of both side surfaces 2 a, right-side downwardor left-side downward of FIG. 1 so as to flow apart from both sidesurfaces 2 a, while keeping a steady flow. Accordingly, the downwash Dreaches the ground surface as a steady flow irrespective of the fuselage2, allowing the chemicals to adhere even to the back of leaves of cropsto be sprayed.

[0039] In the helicopter 1 of the embodiment, the flow control plates 8are mounted at the lower portions of both side surfaces 2 a so as toguide the downwash D outward apart from the fuselage 2, which preventsthe downwash D from flowing into a lower space U of the fuselage 2 (seeFIG. 1). This prevents generation of irregular air current at the lowerspace U of the fuselage 2, thereby preventing chemicals from adhering tothe lower surface 2 b of the fuselage 2. This improves sprayingefficiency and also eliminates removing work of chemicals adhering tothe lower surface 2 b of the fuselage 2.

[0040] When chemicals adhere to the fuselage lower surface 2 b, thechemicals are condensed to high concentration. When the highlyconcentrated chemicals are removed at a different place other than thesprayed place, it sometimes causes environmental pollution. However, theflow control plates 8 mounted on the helicopter 1 of the embodimentprevents chemicals from adhering to the lower surface 2 b of thefuselage 2, avoiding the environmental pollution caused by the removalof the chemicals.

[0041] If adopted the technology that uses nozzles disposed apart fromthe helicopter fuselage 2 (see FIG. 7), supporting members havingnozzles mounted thereon need to be long, which increases body weight andsometimes decreases spraying efficiency due to disorderly supply ofchemicals to the nozzles. On the other hand, the helicopter 1 of theembodiment is provided with the flow control plates 8, which preventschemicals from adhering to the lower surface 2 b of the fuselage 2,allowing the nozzles to be disposed on the lower surface 2 b of thefuselage 2. This disposition allows reducing the body weight and alsoimproving spraying efficiency with stable supply of chemicals or thelike.

[0042] The helicopter 1 of the embodiment is provided with the flowcontrol plates 8 at the lower portions of both side surfaces 2 a of thefuselage 2, which suppresses the generation of irregular air current atthe lower space U of the fuselage 2. Therefore, the body posture can bestabilized, and further body controllability can be remarkably improvedduring the flight such as the spraying flight in which low speed almosthovering is sustained at the height of having high influence of groundeffect.

Second Embodiment

[0043] A description will be given of the structure of a helicopter 10according to a second embodiment with reference to FIGS. 4 and 5. Thehelicopter 10 of the embodiment is such that particular flow channelsare provided within the fuselage 2 of the helicopter 1 according to thefirst embodiment, each flow channel guiding the downwash D on an upperside of the fuselage 2 to the lower space U of the fuselage 2.Therefore, the same elements as corresponding elements of the helicopter1 are designated by the same reference numerals.

[0044] There are provided at the front of the fuselage 2 of thehelicopter 10 an upper opening portion 9 a and a lower opening portion 9b, and at front side within the fuselage 2 a hollow portion 9 c (seeFIGS. 4 and 5). These upper opening portion 9 a, lower opening portion 9b and hollow portion 9 c form a flow channel in the present invention.The downwash D generated by the rotation of the main rotor 4 of thehelicopter 10 flows from the upper opening portion 9 a into the hollowportion 9 c of the fuselage 2, and flows out from the lower openingportion 9 b to the lower space U.

[0045] There are also provided at the rear of the fuselage 2 of thehelicopter 10 an upper opening portion 9 d and a lower opening portion 9e, and at rear side within the fuselage 2 a hollow portion 9 f (see FIG.5). These upper opening portion 9 d, hollow portion 9 f and loweropening portion 9 e form another flow channel in the present invention.The downwash D generated by the rotation of the main rotor 4 flows fromthe upper opening portion 9 d into the hollow portion 9 f, and flows outfrom the lower opening portion 9 e to the lower space U.

[0046] In the helicopter 10 of the embodiment, the downwash D over thefuselage 2 can be guided to the lower space U through the flow channelswithin the fuselage 2, the channels being formed by the upper openingportions 9 a and 9 d of the fuselage 2, the hollow portions 9 c and 9 fwithin the fuselage 2, and the lower opening portions 9 b and 9 e of thefuselage 2, respectively, (see FIGS. 4 and 5). Therefore, the air isreplenished to the lower space U of the fuselage 2, which always keepsthe pressure of the lower space U positive. This positive pressuresecurely prevents the downwash D, which flows along both side surfaces 2a and the flow control plates 8, from flowing into the lower space U,thereby effectively suppressing the generation of irregular air currentat the lower space U.

[0047] The flow control plates 8 in the embodiments are attached in atruncated chevron shape when viewed from the front (extending right-sidedownward or left-side downward in FIGS. 1 and 4), but the attachingangle of the flow control plate 8 with respect to the side surface 2 ais properly changeable. Further, the flow control plates 8 which areextendable and retractable may be provided, the plates 8 may be extendedoutward from the side surfaces 2 a during spraying chemicals, andretracted into the fuselage 2 during normal flights.

[0048] In the embodiments, the flow control plates 8 are providedsymmetrical to each other at both side surfaces 2 a (see FIGS. 1 and 4),but they may not be always symmetrical. Especially, when flowingdirections of the downwash D considerably differ between right side andleft side of the fuselage 2 depending on rotating directions of the mainrotor 4, the flow control plates 8 may be preferably provided dependingon the flowing directions of the downwash D.

[0049] Further, the flow control plates 8 in the embodiments are mountedexemplarily at the lower portions of both side surfaces 2 a (see FIGS. 1and 4), but may be mounted at sides of the lower surface 2 b of thefuselage 2 (neighboring the side surfaces 2 a) extending downward on aslant (right-side downward and left-side downward in FIGS. 1 and 4).Even with the flow control plates 8 thus mounted at the sides of thelower surface 2 b of the fuselage 2, the downwash D flowing along theside surfaces 2 a can be guided outward apart from the fuselage 2.

[0050] The flow control plates 8 in the embodiments are employed as theflow control device and the projecting member, but a block type membermay be employed as the flow control device and the projecting memberinstead of the plate type member. That is, if a structure has a functionof guiding the downwash D to flow along the side surfaces 2 a outwardapart from the fuselage 2, the structure of any kind can be employed asthe flow control device and the projecting member.

[0051] In the second embodiment, while the flow channels are formedwithin the fuselage 2 with the opening portions provided at the upperand lower portions of the fuselage 2 so as to pass through the hollowportions, it is not always necessary to provide walls or the like alongthe flow channels. The shape of the flow channels (areas/shapes of theupper opening portions 9 a, 9 d and the lower opening portions 9 b, 9 e,and volumes/shapes of the hollow portions 9 c, 9 f) may also be properlydecided according to flowing speed and the like of the downwash D.

[0052] According to the present invention, with the flow control deviceprovided, extending downward, at one of the lower portion of thefuselage side surface and the portion on the lower surface of thefuselage near the side surface, the downwash flowing along the fuselageside surfaces is guided outward apart from the fuselage, maintaining asteady flow. Therefore, it can effectively utilize the downwash whendiffusing chemicals or the like by the helicopter.

[0053] Also, according the present invention, the flow control device orthe projection member prevents the downwash from flowing into the underside of the fuselage, which suppresses generation of irregular aircurrent under the fuselage. This air current prevents the chemicals fromadhering to the fuselage lower surface when the helicopter sprays thechemicals or the like, to thereby improve spraying efficiency and alsoeliminate removing work of the chemicals adhering to the fuselage lowersurface.

[0054] Further, by providing the flow channels within the fuselage forguiding the downwash on the upper side of the fuselage to the lower sideof the fuselage, it is securely prevented that the downwash flowingalong the fuselage side surfaces flows into the lower side of thefuselage, thereby effectively suppressing the generation of irregularair current at the lower side of the fuselage.

[0055] The entire disclosure of Japanese Patent Application Nos. Tokugan2003-146403 which was filed on May 23, 2003, including specification,claims, drawings and summary is incorporated herein by reference in itsentirety.

What is claimed is:
 1. A helicopter comprising: a flow control deviceprovided at one of a lower portion of a side surface of a fuselage and aportion on a lower surface of the fuselage near the side surface andextending downward.
 2. A helicopter comprising: a flow control deviceprovided at one of a lower portion of a side surface of a fuselage and aportion on a lower surface of the fuselage near the side surface, forguiding a downwash flowing along the side surface of the fuselage toflow apart from the fuselage.
 3. A helicopter comprising: a projectionmember provided at one of a lower portion of a side surface of afuselage and a portion on a lower surface of the fuselage near the sidesurface and projecting downward.
 4. The helicopter as claimed in claim1, further comprising a flow channel within the fuselage for guiding adownwash on an upper side of the fuselage to a lower side of thefuselage.
 5. The helicopter as claimed in claim 2, further comprising aflow channel within the fuselage for guiding a downwash on an upper sideof the fuselage to a lower side of the fuselage.
 6. The helicopter asclaimed in claim 3, further comprising a flow channel within thefuselage for guiding a downwash on an upper side of the fuselage to alower side of the fuselage.
 7. The helicopter as claimed in claim 1,wherein the flow control device is provided at almost entire length ofthe lower portion of the side surface.
 8. The helicopter as claimed inclaim 2, wherein the flow control device is provided at almost entirelength of the lower portion of the side surface.
 9. The helicopter asclaimed in claim 3, wherein the projection member is provided at almostentire length of the lower portion of the side surface.
 10. Thehelicopter as claimed in claim 1, wherein the flow control device isdividedly provided at a front portion, a center portion and a rearportion of the side surface of the fuselage.
 11. The helicopter asclaimed in claim 2, wherein the flow control device is dividedlyprovided at a front portion, a center portion and a rear portion of theside surface of the fuselage.
 12. The helicopter as claimed in claim 3,wherein the projection member is dividedly provided at a front portion,a center portion and a rear portion of the side surface of the fuselage.13. The helicopter as claimed in claim 1, wherein the flow controldevice is made of any one of a metal, a synthetic resin, a rubbermaterial, an wood, and a composite material thereof.
 14. The helicopteras claimed in claim 2, wherein the flow control device is made of anyone of a metal, a synthetic resin, a rubber material, an wood, and acomposite material thereof.
 15. The helicopter as claimed in claim 3,wherein the projection member is made of any one of a metal, a syntheticresin, a rubber material, an wood, and a composite material thereof. 16.The helicopter as claimed in claim 1, wherein a height of the flowcontrol device is set to larger value than a thickness of a boundarylayer on the side surface, in which the downwash is under an influenceof viscosity by the side surface.
 17. The helicopter as claimed in claim2, wherein a height of the flow control device is set to larger valuethan a thickness of a boundary layer on the side surface, in which thedownwash is under an influence of viscosity by the side surface.
 18. Thehelicopter as claimed in claim 3, wherein a height of the projectionmember is set to larger value than a thickness of a boundary layer onthe side surface, in which the downwash is under an influence ofviscosity by the side surface.
 19. The helicopter as claimed in claim 3,wherein an attaching angle of the projection member with respect to theside surface is changeable.
 20. The helicopter as claimed in claim 3,wherein the projection member is extendable and retractable.